process raya line depicting the path that a firm can follow in expanding OUTPUT where technical constraints mean that FACTOR INPUTS must be used in fixed proportions in a given production process. Fig. 153 shows the production options open to a firm that has a choice from just three processes, A, B and C, each of which uses capital and labour in fixed proportions. If this firm wanted to produce, say, 100 units of output per period, then it could produce 100 units by settling at point d using process A, or point e using process B, or point fusing process C. However, it cannot choose any combination of inputs along the line joining d, e and f because such intermediate combinations are not technically feasible. See ISOQUANT CURVE, ISOQUANT MAP, PRODUCTION FUNCTION.
Collins Dictionary of Economics, 4th ed. © C. Pass, B. Lowes, L. Davies 2005